A creatinine deiminase modified polyaniline electrode for creatinine analysis Original Research Article

By cross-linking creatinine deiminase onto a polyaniline–Nafion composite electrode which effectively senses the ammonium ion, a very sensitive creatinine biosensor was formed. Parameters, such as applied potential, pH of buffer solutions, flow rate of carrier, that may affect the performance of the creatinine biosensor were studied. With the developed creatinine biosensor, a detection limit as low as 0.5 μM and a response time of 60 s were obtained in a flow-injection system. A relative standard deviation of 1.6% (n = 13) was obtained for the successive analysis of a 0.1 mM standard creatinine solution. By following a developed pretreatment procedure which effectively removes the endogenous ammonium ions in body fluid, the determination of creatinine in urine sample was demonstrated.